Ropivacaine-induced toxicity with overdose suspected after axillary brachial plexus block

Abstract

Ropivacaine has a high threshold for systemic toxicity. We report and highlight a rare case in which an overdose of ropivacaine was suspected of leading to a generalized convulsion following the injection of this agent for axillary brachial plexus block (ABPB). A 25-year-old woman (height, 153 cm; weight, 48 kg; American Society of Anesthesiologists physical status I) was scheduled for finger surgery with ABPB. The perivascular sheath was identified by fascial clicks. We administered 300 mg (6.25 mg x kg(-1)) ropivacaine, while confirming that no blood flow was observed in the injection line by repeated negative aspiration tests. Ten minutes after the injection, most sensory and motor nerves were blocked effectively. Thirteen minutes after the administration, the patient lost consciousness and convulsed suddenly. No severe symptoms of cardiovascular toxicity occurred. The concentration of ropivacaine in a venous blood sample taken 28 min after the ropivacaine injection was 3.65 microg x ml(-1). She recovered with no sequelae. Limited cases have indicated high efficacy and sufficient safety for the use of 300 mg ropivacaine for ABPB. However, the toxic threshold of ropivacaine remains unclear, and the dose should be calculated in relation to the weight of the patient to prevent severe toxic complications.

Use of ropivacain and lidocaine for axillary plexus blockade

“…However, rare cases of toxic reaction have been reported in connection with brachial plexus blocks and even cases with cardiac arrest following epidural application of Ropivacaine have been noted. [18] Dalens reported that Ropivacaine concentration did not reach threshold in paediatric patients although large doses (3mg/kg) of the 0.5% solution had been administered for illio-inguinal blocks. [19] Cardio-toxicity is lower for Ropivacaine than Bupivacaine or Levobupivacaine.…”

Midazolam in rabbits terminates dysrhythmias caused by intracerebroventricular ropivacaine

“…Seizure activity may herald the onset of myocardial depression and ventricular arrhythmias that are often refractory to treatment (Kimura et al, 2007;Copeland et al, 2008;Wan et al, 2010). However, in our study, no animals suffered seizures in response to icv ropivacaine administration.…”

One dose fits all? local anaesthetic dosing, clinical trials and safety

“…The accompanying editorial by McGlennan and Sherrat [3] contains inaccuracies in their description of the recommended National Early Warning Score (NEWS) and vital signs chart for adult patients [4]. It states that "…The weightings assigned…(in NEWS)…were not steeped in science, rather mainly based on NEWSDIG's members' clinical opinions and their views of existing EWS…" This is incorrect; NEWS is derived from the Vital-PAC Early Warning Score (ViEWS), the scoring bands of which were deliberately adjusted to maximise its ability to discriminate in-hospital death within 24 hours of a vital signs dataset [2].…”

“…Whilst no patient demonstrated symptoms or signs of LAST, the onset can be 10-30 minutes [3,5], with peak plasma ropivicaine concentrations reported 30 minutes following injection [5]. As study patients received a general anaesthetic, reporting delayed minor neurological symptoms associated with LAST may not have been possible.…”

“…A risk with larger doses is LA systemic toxicity (LAST). Various factors influence plasma concentrations of LAs, including injection site, comorbidities and the dose used, with multiple reports after 300 mg ropivicaine (4.28-8 mg.kg À1 ) [3]. Toxic plasma levels have been demonstrated 24 hours after a 300-mg ropivicaine bolus with continuous 0.2% infusion via femoral and sciatic catheters [4].…”